EnviroNearby

Preble County, Ohio air quality history

Daily Air Quality Index summaries from EPA monitors in Preble, Ohio, 1980–2025.

68%
Good days in 2025
43
Median daily AQI, 2025
2
Days above 100 in 2025
365
Days with an AQI in 2025 (of 365)

In 2025, EPA reported a daily Air Quality Index (AQI) for Preble, Ohio on 365 days. 247 of those days (68%) were in the Good range, and the median daily AQI was 43. That median is about the same as the typical monitored county in Ohio (median 43 across 36 counties), and higher than the typical monitored U.S. county (40). The main pollutant was ozone on 199 days. Across the years with fuller monitoring, the share of Good days fell: an average of 75% in 1980–1982 versus 65% in 2023–2025.

How the days broke down each year

Each bar is one year. The colored segments show the share of monitored days that fell in each AQI category.

Share of monitored days in each AQI category, by year0%25%50%75%100%1980: Good 245 of 324 days1980: Moderate 52 of 324 days1980: Unhealthy for Sensitive Groups 22 of 324 days1980: Unhealthy 5 of 324 days19801981: Good 294 of 363 days1981: Moderate 36 of 363 days1981: Unhealthy for Sensitive Groups 22 of 363 days1981: Unhealthy 10 of 363 days1981: Very Unhealthy 1 of 363 days1982: Good 231 of 339 days1982: Moderate 52 of 339 days1982: Unhealthy for Sensitive Groups 29 of 339 days1982: Unhealthy 21 of 339 days1982: Very Unhealthy 6 of 339 days1983: Good 210 of 295 days1983: Moderate 50 of 295 days1983: Unhealthy for Sensitive Groups 29 of 295 days1983: Unhealthy 6 of 295 days1984: Good 271 of 327 days1984: Moderate 41 of 327 days1984: Unhealthy for Sensitive Groups 13 of 327 days1984: Unhealthy 2 of 327 days1985: Good 280 of 350 days1985: Moderate 55 of 350 days1985: Unhealthy for Sensitive Groups 13 of 350 days1985: Unhealthy 2 of 350 days19851986: Good 218 of 290 days1986: Moderate 50 of 290 days1986: Unhealthy for Sensitive Groups 22 of 290 days1987: Good 113 of 202 days1987: Moderate 61 of 202 days1987: Unhealthy for Sensitive Groups 24 of 202 days1987: Unhealthy 4 of 202 days1988: Good 99 of 208 days1988: Moderate 58 of 208 days1988: Unhealthy for Sensitive Groups 22 of 208 days1988: Unhealthy 23 of 208 days1988: Very Unhealthy 6 of 208 days1989: Good 130 of 210 days1989: Moderate 46 of 210 days1989: Unhealthy for Sensitive Groups 28 of 210 days1989: Unhealthy 6 of 210 days1990: Good 175 of 202 days1990: Moderate 22 of 202 days1990: Unhealthy for Sensitive Groups 5 of 202 days19901991: Good 95 of 214 days1991: Moderate 72 of 214 days1991: Unhealthy for Sensitive Groups 33 of 214 days1991: Unhealthy 12 of 214 days1991: Very Unhealthy 2 of 214 days1992: Good 189 of 210 days1992: Moderate 17 of 210 days1992: Unhealthy for Sensitive Groups 4 of 210 days1993: Good 148 of 214 days1993: Moderate 52 of 214 days1993: Unhealthy for Sensitive Groups 14 of 214 days1994: Good 143 of 214 days1994: Moderate 52 of 214 days1994: Unhealthy for Sensitive Groups 14 of 214 days1994: Unhealthy 5 of 214 days1995: Good 128 of 209 days1995: Moderate 63 of 209 days1995: Unhealthy for Sensitive Groups 13 of 209 days1995: Unhealthy 5 of 209 days19951996: Good 121 of 204 days1996: Moderate 57 of 204 days1996: Unhealthy for Sensitive Groups 21 of 204 days1996: Unhealthy 5 of 204 days1997: Good 134 of 210 days1997: Moderate 56 of 210 days1997: Unhealthy for Sensitive Groups 17 of 210 days1997: Unhealthy 3 of 210 days1998: Good 121 of 211 days1998: Moderate 68 of 211 days1998: Unhealthy for Sensitive Groups 20 of 211 days1998: Unhealthy 2 of 211 days1999: Good 108 of 232 days1999: Moderate 100 of 232 days1999: Unhealthy for Sensitive Groups 21 of 232 days1999: Unhealthy 3 of 232 days2000: Good 124 of 233 days2000: Moderate 99 of 233 days2000: Unhealthy for Sensitive Groups 9 of 233 days2000: Unhealthy 1 of 233 days20002001: Good 137 of 255 days2001: Moderate 103 of 255 days2001: Unhealthy for Sensitive Groups 15 of 255 days2002: Good 115 of 249 days2002: Moderate 107 of 249 days2002: Unhealthy for Sensitive Groups 15 of 249 days2002: Unhealthy 12 of 249 days2003: Good 151 of 245 days2003: Moderate 89 of 245 days2003: Unhealthy for Sensitive Groups 3 of 245 days2003: Unhealthy 2 of 245 days2004: Good 156 of 260 days2004: Moderate 103 of 260 days2004: Unhealthy for Sensitive Groups 1 of 260 days2005: Good 120 of 263 days2005: Moderate 124 of 263 days2005: Unhealthy for Sensitive Groups 18 of 263 days2005: Unhealthy 1 of 263 days20052006: Good 139 of 261 days2006: Moderate 118 of 261 days2006: Unhealthy for Sensitive Groups 4 of 261 days2007: Good 132 of 263 days2007: Moderate 123 of 263 days2007: Unhealthy for Sensitive Groups 8 of 263 days2008: Good 144 of 262 days2008: Moderate 117 of 262 days2008: Unhealthy for Sensitive Groups 1 of 262 days2009: Good 160 of 261 days2009: Moderate 99 of 261 days2009: Unhealthy for Sensitive Groups 2 of 261 days2010: Good 127 of 359 days2010: Moderate 227 of 359 days2010: Unhealthy for Sensitive Groups 5 of 359 days20102011: Good 144 of 365 days2011: Moderate 216 of 365 days2011: Unhealthy for Sensitive Groups 5 of 365 days2012: Good 144 of 366 days2012: Moderate 209 of 366 days2012: Unhealthy for Sensitive Groups 12 of 366 days2012: Unhealthy 1 of 366 days2013: Good 157 of 361 days2013: Moderate 203 of 361 days2013: Unhealthy for Sensitive Groups 1 of 361 days2014: Good 186 of 365 days2014: Moderate 176 of 365 days2014: Unhealthy for Sensitive Groups 3 of 365 days2015: Good 233 of 365 days2015: Moderate 131 of 365 days2015: Unhealthy for Sensitive Groups 1 of 365 days20152016: Good 250 of 366 days2016: Moderate 115 of 366 days2016: Unhealthy for Sensitive Groups 1 of 366 days2017: Good 230 of 365 days2017: Moderate 134 of 365 days2017: Unhealthy for Sensitive Groups 1 of 365 days2018: Good 186 of 365 days2018: Moderate 178 of 365 days2018: Unhealthy for Sensitive Groups 1 of 365 days2019: Good 201 of 364 days2019: Moderate 163 of 364 days2020: Good 262 of 366 days2020: Moderate 103 of 366 days2020: Unhealthy for Sensitive Groups 1 of 366 days20202021: Good 205 of 365 days2021: Moderate 160 of 365 days2022: Good 235 of 365 days2022: Moderate 128 of 365 days2022: Unhealthy for Sensitive Groups 2 of 365 days2023: Good 213 of 358 days2023: Moderate 136 of 358 days2023: Unhealthy for Sensitive Groups 6 of 358 days2023: Unhealthy 2 of 358 days2023: Very Unhealthy 1 of 358 days2024: Good 252 of 366 days2024: Moderate 114 of 366 days2025: Good 247 of 365 days2025: Moderate 116 of 365 days2025: Unhealthy for Sensitive Groups 2 of 365 days2025
  • Good
  • Moderate
  • Unhealthy for Sensitive Groups
  • Unhealthy
  • Very Unhealthy
  • Hazardous

Typical and high-end AQI over time

The median is the middle day of the year. The 90th percentile is the level that only the highest 10% of days exceeded.

Median and 90th-percentile daily AQI, by year0501001502001980: 90th percentile AQI 971981: 90th percentile AQI 871982: 90th percentile AQI 1431983: 90th percentile AQI 1051984: 90th percentile AQI 771985: 90th percentile AQI 771986: 90th percentile AQI 901987: 90th percentile AQI 1081988: 90th percentile AQI 1661989: 90th percentile AQI 1121990: 90th percentile AQI 611991: 90th percentile AQI 1361992: 90th percentile AQI 511993: 90th percentile AQI 931994: 90th percentile AQI 971995: 90th percentile AQI 1001996: 90th percentile AQI 1121997: 90th percentile AQI 1001998: 90th percentile AQI 1011999: 90th percentile AQI 1012000: 90th percentile AQI 852001: 90th percentile AQI 842002: 90th percentile AQI 1052003: 90th percentile AQI 772004: 90th percentile AQI 682005: 90th percentile AQI 932006: 90th percentile AQI 772007: 90th percentile AQI 842008: 90th percentile AQI 742009: 90th percentile AQI 692010: 90th percentile AQI 772011: 90th percentile AQI 772012: 90th percentile AQI 782013: 90th percentile AQI 672014: 90th percentile AQI 672015: 90th percentile AQI 642016: 90th percentile AQI 632017: 90th percentile AQI 602018: 90th percentile AQI 642019: 90th percentile AQI 642020: 90th percentile AQI 582021: 90th percentile AQI 662022: 90th percentile AQI 632023: 90th percentile AQI 692024: 90th percentile AQI 602025: 90th percentile AQI 641980: Median AQI 311981: Median AQI 311982: Median AQI 391983: Median AQI 401984: Median AQI 311985: Median AQI 351986: Median AQI 381987: Median AQI 481988: Median AQI 541989: Median AQI 461990: Median AQI 341991: Median AQI 581992: Median AQI 341993: Median AQI 431994: Median AQI 441995: Median AQI 451996: Median AQI 451997: Median AQI 461998: Median AQI 471999: Median AQI 542000: Median AQI 492001: Median AQI 492002: Median AQI 532003: Median AQI 472004: Median AQI 472005: Median AQI 542006: Median AQI 492007: Median AQI 502008: Median AQI 492009: Median AQI 462010: Median AQI 562011: Median AQI 532012: Median AQI 542013: Median AQI 522014: Median AQI 502015: Median AQI 442016: Median AQI 432017: Median AQI 442018: Median AQI 502019: Median AQI 482020: Median AQI 422021: Median AQI 472022: Median AQI 442023: Median AQI 462024: Median AQI 442025: Median AQI 431980198519901995200020052010201520202025
  • Median daily AQI
  • 90th-percentile daily AQI

Main pollutant by day, 2025

On each monitored day, the AQI reflects whichever measured pollutant had the highest index. This counts how many days each pollutant set the AQI. A pollutant that was not measured here cannot appear.

PollutantDays as main pollutantShare of monitored days
Ozone19955%
Fine particles (PM2.5)16445%
Carbon monoxide (CO)1<1%
Coarse particles (PM10)1<1%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
202536524711620004364115Ozone
202436625211400004460100PM2.5
202335821313662104669204PM2.5
202236523512820004463136PM2.5
20213652051600000476697PM2.5
202036626210310004258101PM2.5
20193642011630000486493PM2.5
201836518617810005064107PM2.5
201736523013410004460108PM2.5
201636625011510004363105Ozone
201536523313110004464105Ozone
201436518617630005067119PM2.5
201336115720310005267113PM2.5
2012366144209121005478159PM2.5
201136514421650005377136PM2.5
201035912722750005677136PM2.5
20092611609920004669119Ozone
200826214411710004974105Ozone
200726313212380005084129Ozone
200626113911840004977126Ozone
2005263120124181005493154Ozone
200426015610310004768105Ozone
20032451518932004777156Ozone
200224911510715120053105179Ozone
2001255137103150004984136Ozone
20002331249991004985164Ozone
19992321081002130054101154Ozone
1998211121682020047101182Ozone
1997210134561730046100182Ozone
1996204121572150045112197Ozone
1995209128631350045100174Ozone
199421414352145004497174Ozone
199321414852140004393129Ozone
19922101891740003451126Ozone
1991214957233122058136209Ozone
19902021752250003461147Ozone
1989210130462860046112187Ozone
1988208995822236054166209Ozone
1987202113612440048108164Ozone
198629021850220003890150Ozone
198535028055132003577161Ozone
198432727141132003177200Ozone
1983295210502960040105177Ozone
19823392315229216039143235Ozone
1981363294362210103187201Ozone
198032424552225003197195Ozone

What this data can and can’t tell you

It is a county-level summary. EPA reports one AQI per day for the county, based on the monitors operating there. Air at a particular street, school or home can differ, especially near roads, industry or wildfire smoke.

It is not a health assessment. The AQI is EPA’s scale for communicating daily air quality. A county’s history can’t tell you what the health risk is for any particular person. For daily conditions and health guidance, see AirNow.

Rules change over time. EPA has revised AQI breakpoints, most recently for fine particles in 2024, so some year-to-year change can reflect the scale rather than the air.

Counties in Ohio with a similar median AQI in 2025

All monitored counties in Ohio

Source: U.S. EPA AirData, “Annual AQI by County” files for 1980–2025 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem